Research project Field and modelling studies of the long-range transport of pollutants on sea spray aerosols

In previous work, funded by the Swedish Research Council (VR) and the Swedish Research Council for Sustainable Development (FORMAS), we demonstrated in the lab that surface active pollutants such as perfluoroalkyl acids (PFAAs) are enriched hundreds of thousands of times in nascent sea spray aerosols (SSA) relative to the bulk water. Due to a lack of research in this field, the transport of pollutants on SSA is neglected by environmental chemists and excluded from global transport and fate models. Although our previous laboratory work is a key piece of evidence for proving the importance of SSA as a source of PFAAs to the atmosphere, a stronger evidence base, including field studies and mechanistic modelling studies, is further needed to determine the relative importance of SSA transport compared to other sources. PFAAs are ideal model pollutants for better understanding the process. In this project, we will (1) conduct fieldwork to determine if air concentrations of PFAAs are correlated with tracers of SSA (i.e. sodium and magnesium ions) in ambient air samples collected at multiple global coastal locations and (2) conduct global modelling studies to determine if ocean-to-air transport of PFAAs on SSA is an important source of PFAAs relative to other sources (e.g. precursor transformation and direct discharges from manufacturing). The new data gathered will provide strong evidence for the importance of this previously overlooked atmospheric transport process for pollutants.